Apparatus for recovering fine gold.



J. H. ALLING.

APPARATUS FOR REGOVERING FINE GOLD.

APPLIOATION FILED MAY 4 1908.

Patented Feb. 1, 11910.

WITNESSES:

11v VENTOR,

A TTORNE Y.

Janna H. amine, or SAN FRANCISCO, canrronmn.

JPA'IUS FUR RECOVERING FINE GOLD.

earns.

Specification of Letters Patent.

Application filed May 4, 1908.

Serial No. 430,696.

4 To all whom it may concern} and useful Improvements in Apparatus for Recovering Fine Gold, of which the following is a specification.

The object of the present invention is to provide an apparatus for the recovery of very fine particles of gold, silver, and platinum.

There are known to exist largcnatural deposits of gold-bearing material whlch are comparatively rich in the precious metal, but from which the gold cannot be recovered by any known process except smelting; and as the cost of smeltingis from $5.00 to $7.00 a ton, besides the freight, the cost by smelting is prohibitive except for very valuable ores. The reason why such gold cannot be recovered by ordinary methods is, either that the particles of gold are so extremely minute, that they floataway, and cannot be arrested in the ordinary sluices, amalgamators, and other apparatus in general use, or that the particles of\gold are incased in capsules oi. material which has to be removed by grinding, so that theparticles of gold will be separated as free gold, and recovered by amalgamation. But, to dothis the material must beground to such a degree of fineness,'say 100 mesh or smaller, that, in

this case also, the ordinary methods of re coveringthis very fine gold proves impracticable ortoo expensive. In-addition, there are, in the States of California, Nevada and elsewhere, large"'deposits of tailings from former Workings of ore, which tailings contain a large amount of gold-,but' insuch a finely'divided state as not to be recoverable by ordinary methods; Also many of these dumps, while containing finely divided gold, also contain such large quantities of copper, iron or arsenical pyrites, and other baser ores, that the ordinary cyanid process cannot be profitably applied thereto, on account ofthe'baser ores consuming too large a proportion of the cyanid. These can be worked by my apparatus.

In the accompanying drawing, Figurel is a plan view, of the apparatus; Fig. 2 is a broken side view of the same; Fig. 3 is an enlarged broken detail longitudinal section of the same; Fig. 4: lS a cross section on the -cury, shown at 7.

line 4-4 of Fig. 3'; Fig.5 is an enlarged broken detail longitudinal section through an anode plate and mercury'pocket.

Referring to the drawing, 1 indicates a sluice box, which is sloped at a greater angle than are thesluice boxes used for the recovery of gold in the ordinary processes. In the bottom of said sluice boxis a con tinuous amalgamat'ing plate 2 formed at suitable intervals into pockets or troughs 3. Each pocket is formed with a rear wall 4:

having a considerable slope, nearly 15 degrees, to the vertical, a front wall 5 slopin slightly backward from the vertical, an

a bottom substantially horizontal. In each pocket is placed a .suiiicient quantity of mer- The sides of the sluice box are formed with oblique grooves 8 inclined rearwardly upward, and across said sluice box extend anode amalgamating plates 9, with their edges in said grooves. The lower edges of said plates extend to within a short distance, say of an inch, from the upper surface of the mercury in the troughs or pockets The height of each plate can bejadjusted by means of adjusting screws 10 screwed through lips 11 extending from the plates over the sides ofthe sluice box,

said screws resting on the tops of said sides. Extending along one side. of the slulcebox 1s an electric conductor 13, connected to the positive pole of an electric current generator I 14. This conductor is connected by conductors 15 with the severalplates; 9, which thus serveas anodes for currents of electricity. The conductors 13 and 15 are made of large conductivity .in proportion to thecurrent, 1n

Fatented Feb. I, IFIU,

tween the tops of the sides of the sluice box,

substantially midway betweeni the 'anod'e plates 9. In certain cases, 'itmay,be do sirable to interpose, more-than one swinging anode between eachqpair of anode plates. These cross bars 17, are electrically gconnected to the longitudinaliconductor 13.,

The cathode plate- 2, isoonnected by a wire 19 tothe source of the electric current. f The material, having been first finely pulverized is. fed by a chute 23 into the top of the sluice. box. At the same time there is fed, by aipipe 24:, a sufl'lcient quantity of water, aboutit tons to 1 ton of material, and

through a pipe 32 is fed a small proportion, about 1 to 1000, 2000, or more parts, of a mixture consisting of aqueous solutions ofpotassic cyanid and mercuric chlorid. The proportion of the mixture to the water will vary according to the richness of the material being treated, the rule being to supply, in themercuric chlorid, one ounce of mercury to each ounce of gold in the material. In treating certain ores, I have found satisfactory proportions by weight to be to 1 lb. of potassic cyanid to 2 ozs. mercuric chlorid and 5 gallons of the solution. The addition of the cyanid facilitates the electrolysis and cleans the gold.

The electric current passes from the anode plates and swinging anodes into and through the water and other material flowing down the sluice box and enters the cathode plate 2 in the bottom of the sluice box, either directly, or through the mercury in the trough or pockets 3 thereof.

The density of the current used is comparatively low, being from to 1 ampere for each square foot of cathode surface according to the richness of the material. For the purpose of varying the amount of current for different material a rheostat 20 is provided. I have found a voltage of 5 volts to be satisfactory in practice. An ammeter 21 and volt meter 22 are used to indicate the current and voltage.

By the above described apparatus I have been able to save over 95 er centum of the values of material containing finely divided gold, which cannot be saved by ordinary methods.

It is in order to replenish the aqueous solution of mercuric chlorid with mercury that the surface of the anode is amal amated and since the mercury is continual y being removed from the rear surface of the anode plates by electrolysis, as well as by the impact of the particles of gold thereagainst, it is desirable to replace this mercury as fast as removed, so that there will always be a suflicient coatingef mercury upon the anode plates to obtain a proper action of the apparatus. Many contrivances may be adopted for this purpose and I show herein the following. Upon the front or upper side of each anode 1s formed a narrow chamber 26, the rear wall of said chamber being formed by the anode late itself, and the front wall 27 being para lel to said anode plate. This chamber is, at. suitable intervals of time, suppgied with mercury, and the mercury runs om said chamber through very minute perforations 28 in the anode plate to the rear wall thereof, on which it spreads immediately upon its'emergence from said perforations, forming a thin film or coating upon the silvered surface of the plate. The mercury which tends to collect at the bottom of each trough is drawn off by an overflow pipe 29 running from the bottom of the trough and thence to the side of the apparatus and then upward to such a level, that when the mercury rises to a certain level in its trough it will overflow from said overflow pipe 29 into a conduit 30 leading to a receptacle 31. From this receptacle it can be removed from time to time and retorted or redistributed among the several mercury chambers. By this means the levels of the troughs are maintained constant notwithstanding the continual addition thereto of the mercury coming from the anode plates. Thus there is no loss whatever of mercury, and there can be no flouring of the mercury, on account of the electric current continually passing therethrough.

A great advantage of the above described apparatusover the ordinary treatment by cyaniding is the great saving in the cost of the plant required and the time and labor consumed. For instance, whereas to cyanid a given amount of ore by the ordinary process of cyaniding would require a plant costing, say, $100,000, the same results can be obtained by my apparatus in a plant costing $10,000, and whereas the time required for cyaniding a given amount of ore would, in the cyamding plant above referred to, be from 36 to 72 hours, the same amount of Work by my improved apparatus could be obtained by a continuous flow of about 10 hours, and with practically no cost for labor or manipulation, as compared with a. considerable cost for labor expended in the c anid plant, in addition to great expense for s tilled supervision and chemicals.

I claim 1. An apparatus of the character described comprising an anode having a coating of mercury, a cathode consisting of a pocket adapted to contain mercury, a source of supply of electricity connected to said anode and cathode, and means for continually passing the material to be treated, mixed with a solvent, between said anode and cathode, substantially as described.

2. An apparatus of'the character described comprising an anode having a coating of mercur a cathode consisting of a pocket adapte to contain mercury, a source of su ply of electricity connected to said ano e and cathode, means for replenishing the mercury to the anode, and means for continually passing the material to be treated, mixed with a solvent, between said anode and cathode, substantially as described.

3. An apparatus of the character described comprising an anode having a coating of mercury, a cathode consisting of a pocket adapted to contain mercury, a source of supply of electricity connected to said-anode and cathode, an overflow pipe, connected with said pocket to maintain the mercury at a uniform level therein, and means for con- -to the coated surface erases tin'ually with a solvent, between said anode and cathode substantially as described.

4. An apparatus of the character described comprising an anode having a coating of mercury, a cathode consisting of a pocket adapted to contain mercury, a source of supply of electricity connected to said anode and cathode, means for replenishing the mercury to the anode comprisin a chamber adapted to contain mercury, sai anode hav ing perforations leading from said chamber of the anode, and means for continually passin the material to be treated, mixed with a so vent, between said anode and cathode, substantially as described.

5. In an apparatus of the character described, the combination of a sluice box having pockets in its bottom spaced from each other, adapted to contain mercury, said pockets having non-conducting surfaces, anode plates having their lower edges extending toward said pockets, conductors arranged to electrically connect with mercury in the respective ockets, carbon anode plates between the a oresaid plates, cathode platesbetween the pockets provided with an amalgamated surface, and means for passing electricity from said anode plates to the cathodes through the material down the sluice box, substantially as described.

6. In an apparatus of the character described, the combination of a sluice box hawin pockets in its bottom spaced from each 0t er, adapted to contain -mercury, said pockets having non-conducting surfaces, anode plates havin their lower edges extending toward said pockets, conductors arranged to electrically connect with mercury in the respective pockets, swinging anode plates between the aforesaid plates, cathode plates between thepockets provided with an amalgamated surface, and means for passing electricity from said cathodes through the material flowing down the sluice box, substantially as described.

7. In an apparatus of the character described, the combination of a sluice box, a cathode plate in the bottom thereof formed with a series of pockets adapted to contain mercury, anode plates having their lower edges extending toward said pockets, swinging anodes interposed between said anode plates, the cathode plates between, said pockets being formed with an amalgamated surface, and means for passing a current of electricity from said anode plates to said cathode plates through the material flowing down the sluice box, substantially as described. p v

In testimony whereof l have hereunto set my hand in the presence of two subscribing witnesses.

JAMES H. ALLING. Witnesses:

FnANcIs WRIGHT, l). B. RICHARDS.

anode plates to the 

